1. Field of the Invention
This invention relates to floor sanders. In particular, the present invention relates to a non-rotary, linear reciprocating floor sander with a pair of abrasive platens having coordinated opposing linear sliding movement, which avoids scrapes and visual impediments to a sanded wood floor.
2. Description of the Prior Art
Rotary based floor sanders, which typically operate with either a continuous abrasive belt or a flat rotating abrasive disc, present problems in sanding a floor. For example the rotary motions of the disc or the continuous belt are inherently aggressive, and vibrate greatly during use. Therefore the user has to constantly manually maneuver the floor sander machine as the user lowers the sander to the floor, to avoid deep gouges or scratches into the floor. This requires an expert laborer to skillfully manually manipulate the floor sander without gouging or scratching the floor being sanded.
In addition, rotary floor sanders with a continuous rotating belt, have a soft elastomeric backing, such as rubber or other elastomer behind the abrasive belt. The soft elastomeric backing bends and gives whenever the floor surface is dense, such as where a wood knot is located. As a result, the belt and the rubber backing located behind the belt, adjusts to the dense knot of the wood, goes over the knot, and grinds only the softer wood surrounding the knot. This leaves dips and valleys in the floor areas adjacent to the denser wood knots.
In addition, rotary disk sanders are limited by the radius of the rotating sanding disk, and therefore can not evenly sand the portions of the floor near the corners and edges of the floor. Also when the user of a rotating sander, whether of the continuous belt or rotary disk kind, approaches the corner or wall edge, the user must turn around and move the sander to a different position on the floor. This often causes deep scratches and imperfections in the sanded floor, which then have to be re-sanded manually, upon completion of the work with the rotary sander.
Furthermore, the rotary sanders can not easily follow the grain of the wood being sanded, in a linear direction, without excessive vibrations, which often result in scratches being dug into the floor surface.
Among patents for continuous belt rotary sanders include U.S. Pat. No. 5,341,605 of Tasikas for a dual mode floor sander, having a continuous belt of abrasive material, placed around a sanding drum, wherein the tension of the roller can be modified. In addition U.S. Pat. No. 6,155,917, also of Tasikas, describes a belt sander with a continuous sanding belt. In this patent of Tasikas '917, an extension roll is provided to minimize friction and resultant heat loss, during the sanding process. In Tasikas '917, an anti-friction surface is provided to engage the rear of the sanding belt, to allow pressure to be applied against the belt sanding the floor, without significant heat build-up due to friction.
Another continuous belt sander is noted in U.S. Pat. No. 5,575,710 of Kramer, assigned to Clarke Industries, Inc. of Springdale, Ark., for a floor sander, having a leveling mechanism, to counteract the vertical movement of the chassis and to position the axis of rotation of the sanding head, in a plane which is common within the axis of rotation of the wheels on the frame, thereby avoiding scratches due to misorientation of the floor sander.
Rotary disk sanders provide a rotating sandisk, which rotates about a vertical axis to sand a floor. However, the rotating disk is subject to vibrations and any deviation of the disk off of the vertical axis causes the edges of the sanding disk to grind non-axially into the floor, leaving deep scratches and gauging.
Among related rotary disk sanders include U.S. Pat. Nos. 6,419,565 and 6,202,775 of Mattson, as well as U.S. Patent Publication No. 2001/0002627 A1, also of Mattson, assigned to Floor Style Products, Inc. of Hastings, Mich., for rotary floor finishers which ride behind a power trailer, wherein the user is seated in a tractor-type seating orientation.
Furthermore, U.S. Pat. No. 5,890,954 of Barous describes a floor edger and sander having a rotary sanding disk, as well as an auxiliary disk float member, such as a collection of coil springs, to orient the sanding disk in a generally horizontal position as it is being moved by castors upon the floor being sanded.
U.S. Patent Publication No. US2003/0022612 A1 of Barnes describes a rotating orbital action floor sander, having a plurality of floor sanders.
In addition to the aforementioned mechanical rotating floor sanders, hand operable manual floor sanders are known, wherein the user pushes a handle of the floor sander in a reciprocating linear back and forth motion across the floor.
Among such manually operated floor sander tools include U.S. Pat. No. 1,501,192 of Severns for a floor sander and polisher, having a handle for manually pushing the floor sander across the floor, U.S. Pat. No. 2,429,550 of Hein for a hand-held cabinet finishing tool having a handle as well as a sanding block head and U.S. Pat. No. 5,855,505 of Letts for a sanding surface leveling tool, with a screw driver recess, built into the handle, for manually adjusting screws for tightening the sanding head of the tool. U.S. Pat. No. 5,634,843 of Liu describes a multifunctional grinding wiper including a longitudly extending handle and a grinding wiper for attaching grinding substrates such as emery sheets. Furthermore U.S. Pat. No. 4,927,984 of Taranto describes a hand pushed sanding block tool, having a vacuum attached thereto for removing saw dust.
The aforementioned portable floor sanding devices, either of the rotating disk or continuous belt type, or which are handheld tools, do not provide a reciprocating linear mechanical movements to be applied to the floor.
Reciprocating sanders have been known, however these sanders are typically stationary non moving stand alone machines for sanding of panels or boards, or else are hand held vibrating reciprocating sanders for sanding surface portions of wood furniture components.
However, these small hand-held sanders are not adaptable as portable, mechanical floor sanders, having reciprocating linear floor sander platens moving in opposite directions. Among such stand-alone machines include U.S. Pat. No. 4,864,775 of David for a cross-belt sanding machine having oscillatory movements. However, David '775 requires a continuous belt 12 to be operated, which has the same disadvantage as the continuous belt floor sanders.
In addition, U.S. Pat. No. 4,821,457 of Ianuzzi describes a vertical oscillating spindle sander, whereby the sander radially oscillates a non-circulatory but gyratory motion.
Another gyratory sanding machine for abrasive sandpaper material is described in U.S. Pat. No. 2,334,172 of Champayne. In addition, U.S. Pat. No. 2,455,626 of Traut describes a hand held thumb activatable sander which uses gyratory eccentric motions for converting rotary motions into reciprocating movements.
A sander is described in U.S. Pat. No. 3,943,669 of Stroezel whereby a rotary piston rotates an eccentric shaft to impart movement thereto and an eccentric configuration.
U.S. Pat. No. 2,830,411 of Hartmann describes a hand held reciprocating sanding machine. U.S. Pat. No. 2,790,276 of Sarkis Doctor Acopain describes a hand-held vibratory sanding tool, which provides a reciprocating motion of a sanding strip supporting plate, which confines the movement of the sanding strip to a straight line. Other reciprocating hand held power sanders are shown in U.S. Pat. No. 3,555,743 of Geiger and U.S. Pat. No. 2,755,673 of Dixon.
Further sanders for hand held operation, such as U.S. Pat. Nos. 4,478,010 and 4,475,316, both of Dicke, describe in-line sanders which have module housings, to influence motion of a sanding platen support, which is carried on legs, extending to a base portion, wherein the legs have a low moment of inertia in the direction of the in-line sanding, and a high moment of inertia normal to the direction of the inline sanding, so as to be causing motion in the in-line sanding path only.
However, the aforementioned in-line sanders are not directed towards a manually operated floor sander, as opposed to a hand-held sander for sanding a piece of furniture.